gcd on polynomials over ZZ [closed]
 
  
 
  
 
 
 
 
 
 
    
        
        asked 3 years ago  
 
 Max Alekseyev gravatar image  
 
 
 
 
    
        
        updated 3 years ago  
 
 
 
 
 
In Sage 9.4, in the following code:
 
P.<x> = QQ[]
pol = 2*x^2 + 4*x + 6
print( gcd(pol) )
print( gcd(pol.change_ring(ZZ)) )
 
The first gcd works fine, while the second gcd results in 
 
TypeError: object of type 'sage.rings.polynomial.polynomial_integer_dense_flint.Polynomial_integer_dense_flint' has no len()
 
There is a workaround by using gcd(pol.coefficients()), but I wonder if above error is a bug.
 
PS. This gcd is essentially what is called the content of a polynomial. Surprisingly, .content() is defined for multivariate polynomials but not for univariate ones.
 
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Closed for the following reason
      question is not relevant or outdated by
      Max Alekseyev 

      close date 2023-05-07 17:44:44.158436
 
 
Comments
1
This smells of an implementation oversight which, IMHO, should be filed as a bug...
Emmanuel Charpentier gravatar imageEmmanuel Charpentier (
    
        3 years ago
    )
1
It works for me on 9.5.beta4:
sage: P.<x> = QQ[]
....: pol = 2*x^2 + 4*x + 6
....: print( gcd(pol) )
....: print( gcd(pol.change_ring(ZZ)) )
2
2
tmonteil gravatar imagetmonteil (
    
        3 years ago
    )
That is good to know. Does 9.5 have .content() defined for univariate polynomials by any chance?
Max Alekseyev gravatar imageMax Alekseyev (
    
        3 years ago
    )
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